Spinnerette



H. J. JONES SPINNERETTE Nov. 7, 1944.

Filed July 7, 1942' Bnventor N cfr/022635 Gttorneg Patented Nov. 7, 1944SPINNERETTE Harry John Jones, Mllburn, N. J., assignor to Baker & Co.Inc., Newark, N. J., a corporation of New Jersey Application July 7,1942, Serial No. 450,067

3 Claims.

This invention relates in general to spinnerettes for the extrusion oforganic viscous substances in the spinning; of artificial laments and isconcerned in particular with the provision of spinnerettes for thespinning of synthetic substances such as syntheti-c polyamides and otherpolymerization products of fiber forming ability such, for instance, asthose described lmore particularly in U. S. Letters Patents No.2,071,250, No. 2,071,- 251, No. 2,071,252, No. 2,071,253, No. 2,130,947,and No. 2,130,948.

This application is a continuation-impart of my earlier applicationSerial No. 249,360, filed January 5, 1939, and my application Serial No.422,648, led December 12, 1941.

Spinnerettes for the extrusion of organic substances in the spinning ofrayon or other artiiicial filaments, bers, or yarns, usually comprise aspinning plate in the form of a disc or cup provided witha plurality ofminute orices, usually from 0.001" to 0.032" in diameter, through whichthe viscous mass, the viscosity of which often approaches the dry state,is extruded to form the filaments and the like. Spinnerettes areconstructed of precious metal in the spinning of filaments and the likein the viscose process, and of base metal in the spinning of laments andthe like in the acetate and cuprammonium processes.

It is one object of this invention to provide a base metal spinnerettewhich shall be superior to base metal spinnerettes heretofore known. Itis another object of this invention to provide a base metal spinnerettewhich shall be suitable for the spinning of artificial laments and thelike from polymerization products of ber forming ability. It is afurther object of the invention to provide such spinnerettes whic-hshall be capable of spinning such artificial filaments and the likeunder pressure and at elevated temperatures, such as several hundredpounds pressure per square inch and at a temperature of at least 200 C.Other objects and advantages of the invention will appear from thedescription thereof hereinafter following.

In the spinning of artificial laments in the acetate and cuprammoniumprocesses base metals such as nickel, nickel alloys, tantalum, andstainless steels containing nickel, have been found suitable. Suchspinnerettes are, however, not always satisfactory under severeoperating conditions and are in particular not especially suitable inthe spinning of articial filaments and the like from syntheticlpolyamides and other polymerization products of fiber forming ability,

such as described in the aforesaid U. S. Letters Patents No. 2,071,250,No. 2,071,251, No. 2,071,252, No. 2,071,253, No. 2,130,947, and No.2,130,948, where spinning takes place under pressure and at elevatedtemperature and under otherwise exacting operating conditions resultingfrom the nature of the extrusion mass.

I have discovered that the objects of ymy nventon can be achieved andthat a superior base metal spinnerette for the purposes described can beproduced by constructing such spinnerette of a chromium steel containingnot less than 14% but not more than 20%` chromium, preferably fromapproximately 17% to approximately 19% chromium, provided such steel issubstantially free from nickel. Such steel should contain not more than0.5% carbon, but may contain slight impurities sometimes encountered inchromium steels such as manganese. phosphorus, molyb-` denum, sulphur,silicon, and copper.

The spinnerette of the invention is illustrated in the accompanyingdrawing in which:

Fig.A 1 is a top plan View of one type of spinnerette,

Fig. 2 is a fragmentary enlarged vertical sectional view through thespinnerette Wall, and

Fig. 3 is a transverse vertical sectional view on an enlarged scalethrough an extrusion apparatus including another type of spinnerette.

Fig. 1 shows the spinnerette in the form of an extrusion plate or IdiscI, constructed of stainless steel substantially free from nickel andconsisting essentially of iron and chromium containing from 14% to 20%chromium, and provided with extrusion orifices or holes 2. As shown inFig. 2 the extrusion orices 2 may com-prise a cylindrical counterbore 3,an intermediate portion 4, and an outlet portion 5, the walls of thethree portions forming a smooth and uninterrupted ow surface. Fig. 3shows a cup shaped type of spinnerette having a cup shaped body 6,likewise constructed of the same stainless steel as in the case of discl of Fig. 1, the said cup shaped body 6 comprising a bottom wall 1 andcylin-drical walls 8, the bottom wall being provided with mately 18%chromium and 0.10% carbon, rest iron, and free from nickel.

Such spinnerettes according to the invention are extremely hard and willwithstand the highest pressures normally encountered in the productionof artificial filaments and the like from synthetic polyamides and otherfiber forming polymerization products. At the same time suchspinnerettes are capable of being operated at the elevated temperaturesusual in the spinning of such synthetic substances and are not attackedchemically by the extrusion mass. While permitting the formation ofminute orifices therein the metal of the spinnerette is sufficientlystrong to withstand abrasion and wear, in the presence of the flowingextrusion mass, so that the constancy of the dimensions of the minuteextrusion orifices is maintained. The walls of the orifices in suchspinnerette are capable of taking, and retaining throughout theoperation, a beautiful high polish, and as the walls of such orifices donot become roughened in use, whether by chemical or mechanical action,and as the orifices are not deformed under pressure, assuming a properthickness of extrusion plate in proportion to the pressure exertedthereupon, the extrusion mass flows quickly and freely through theorifices of the spinnerette, particularly as the nature of thespinnerette is such that clogging of orifices is kept at a minimum, withthe result that the spinning process can operate at relatively highspeed to produce filaments and the like of uniform cross-section andhigh quality. Another feature of the spinnerette in accordance with theinvention is that it can be cleaned with boiling nitric acid, or othersuitable cleaning acids, without interference with the smooth surface ofthe extrusion orifices. Enlargement of the orifices, which likewisewould result in the Production of filaments of irregular or poorquality, is fully prevented in the spinnerette of the invention, anddamage by rough handling or other abuse by the operator is kept at aminimium.

The spinnerette of the invention is designed especially for the spinningof synthetic polyamides and other polymerization products of ber formingability, as aforesaid, where base metal spinnerettes, as heretoforeknown, including such stainless steel spinnerettes as heretofore known,are not sufiiciently suitable. Such polymerization products can beextruded, through my spinnerettes, by the wet process, the dry process,or the melt process. I have also found that the spinnerettes accordingto the invention are Superior to such base metal spinnerettes asheretofore known, even in the spinning of artificial filaments and thelike from other synthetic substances, as in the acetate and cuprammoniumprocesses, where, as distinguished from the spinning of fiber formingpolymerization products, spinnerettes of other base metals, such asstainless steels containing substantial quantities of nickel, forinstance from '7% to 10% nickel, are suitable as such.

In providing spinneretttes in accordance with the invention it is ofcritical importance, in order to produce a spinnerette having thesuperior qualities described, that the chromium steel, containing from14% to 20% chromium, be substantially free from nickel. I have foundthat the best spinnerettes are produced from such steels which are freefrom nickel, although it will be understood that a minor quantity ofnickel will not substantially interfere with the performance of myspinnerettes as the effect of nickel progressively decreases withdecreasing amounts; in which connection I have found, however, that aproportion of 2% nickel is already in excess of that quantity of nickelwhich I consider permissible in the construction material of thespinnerettes according to the invention. The term substantially freefrom nickel as herein used is meant, therefore, to indicate that theconstruction material of the spinnerette contains definitely less than2% nickel and is preferably entirely free from nickel. The presence ofnickel tends to decrease the general resistance of the spinnerette toadverse mechanical and chemical factors and affects, for instance, theability of the spinnerette to withstand cleaning with boiling nitricacid. The marked superiority of the spinnerette of the invention overother spinnerettes of base metal, ceases when the chromium content fallsbelow 14% or exceeds 20%, or when the chromium steel contains 2% or moreof nickel.

The spinnerettes of the invention as employed in practice in thespinning of artificial filaments and the like from fiber formingpolymerization products, designed for high pressure operations atelevated temperatures, are formed in the shape of a disc having athickness of about 0.2" and provided with orifices, illustratedparticularly in Fig. 2, consisting of a relatively narrow cylindricaloutlet portion 5, the inlet portion 3 comprising a cylindricalcounterbore having a diameter substantially larger than that of theoutlet portion, and an intermediate portion 4 having a tapered walldirectly connecting the end of the inlet portion with the beginning ofthe outlet portion, the walls of the three portions forming a smooth anduninterrupted flow surface. The shape of such orifice is moreparticularly described in my co-pending application Serial No. 422,648,filed December l2, 1941, now Patent #2,341,555.

In general, the thickness of the spinning plate ranges from 0.06 to0.4", and the extrusion orifices have a cross-section, at the extrusionend, of the order of 0.001 to 0.032.

What I claim is:

1. A spinnerette for the spinning of artificial filaments and the likefrom synthetic polymerization products' of fiber formingabilityhconstructed of stainless steel substantially free from nickeland consisting essentially of iron and chromium wherein the chromiumcontent doesngtmfall below 14% and does not exceed 20%.

2. A spinnerette for the spinning of artificial filaments and the likefrom synthetic polymerization products of ber forming ability,constructed of stainless steel substantially free from nickel andconsisting essentially of iron and chromium wherein the chromium contentdoes not fall below 17% and does not exceed 19% and wherein the carboncontent does not exceed 0.5%.

3. A spinnerette for the spinning of artificial filaments and the likefrom synthetic polymerization products of fiber forming ability,constructed of stainless steel substantially free from nickel andconsisting essentially of iron and chromium wherein the chromium contentcomprises about 18% and the carbon content comprises about 0.10%.

HARRY JOHN JONES.

